/*=====================================================================*
 *                   Copyright (C) 2011 Paul Mineiro                   *
 * All rights reserved.                                                *
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 * Redistribution and use in source and binary forms, with             *
 * or without modification, are permitted provided that the            *
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 *     above copyright notice, this list of conditions and             *
 *     the following disclaimer.                                       *
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 *     * Redistributions in binary form must reproduce the             *
 *     above copyright notice, this list of conditions and             *
 *     the following disclaimer in the documentation and/or            *
 *     other materials provided with the distribution.                 *
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 *     * Neither the name of Paul Mineiro nor the names                *
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 *     products derived from this software without specific            *
 *     prior written permission.                                       *
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 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND              *
 * CONTRIBUTORS "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES,         *
 * INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES               *
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 * Contact: Paul Mineiro <paul@mineiro.com>                            *
 *=====================================================================*/

#include "qfunc.h"
#include "prating.c"

/* TODO: use of trampolines to enforce alpha[k][k] = 0 might be inefficient.
 * have to profile and see if this is a problem.
 * i could totally sidestep this by declaring alpha non-const, but there
 * is a certain dirtiness to that.  otoh, this _is_ C.
 */

double
qfunc (const double*            alpha,
       unsigned int             n_workers,
       unsigned int             n_labels,
       const double*            logbeta,
       unsigned int             n_images,
       const double*            pz,
       const double*            priorz,
       const Rating*            ratings,
       unsigned int             n_ratings,
       const Distribution*      prioralpha,
       const Distribution*      priorlogbeta,
       int                      symmetric)
{
  double q = 0;

  for (unsigned int i = 0; i < n_images; ++i)
    {
      for (unsigned int j = 0; j < n_labels; ++j)
        {
          q += pz[j + i * n_labels] * log (priorz[j]);
        }
    }

  for (unsigned int i = 0; i < n_ratings; ++i)
    {
      for (unsigned int j = 0; j < n_labels; ++j)
        {
          auto double alphafunc (unsigned int);
          double alphafunc (unsigned int k)
            {
              if (k == j) { return 0.0; }
              else if (symmetric && k < j) 
                {
                  return alpha[ratings[i].worker * n_labels * n_labels +
                               k * n_labels +
                               j]; 
                }
              else 
                { 
                  return alpha[ratings[i].worker * n_labels * n_labels +
                               j * n_labels +
                               k]; 
                }
            }

          q += pz[j + ratings[i].image * n_labels] * 
               logprating (ratings[i].rating,
                           alphafunc,
                           logbeta[ratings[i].image],
                           n_labels);
        }
    }

  for (unsigned int i = 0; i < n_workers; ++i)
    {
      for (unsigned int j = 0; j < n_labels; ++j)
        {
          for (unsigned int k = 0; k < n_labels; ++k)
            {
              if (k == j)
                {
                  q += prioralpha->logpdf (0.0, prioralpha);
                }
              else if (symmetric && k < j)
                {
                  q += prioralpha->logpdf (alpha[i * n_labels * n_labels +
                                                 k * n_labels +
                                                 j],
                                           prioralpha);
                }
              else
                {
                  q += prioralpha->logpdf (alpha[i * n_labels * n_labels +
                                                 j * n_labels +
                                                 k],
                                           prioralpha);
                }
            }
        }
    }

  for (unsigned int i = 0; i < n_images; ++i)
    {
      q += priorlogbeta->logpdf (logbeta[i], priorlogbeta);
    }

  return q;
}

void
dqfunc (double*                 dalpha,
        double*                 dlogbeta,
        const double*           alpha,
        unsigned int            n_workers,
        unsigned int            n_labels,
        const double*           logbeta,
        unsigned int            n_images,
        const double*           pz,
        const Rating*           ratings,
        unsigned int            n_ratings,
        const Distribution*     prioralpha,
        const Distribution*     priorlogbeta,
        int                     symmetric)
{
  memset (dalpha, 0, n_workers * n_labels * n_labels * sizeof (dalpha[0]));
  memset (dlogbeta, 0, n_images * sizeof (dlogbeta[0]));

  for (unsigned int i = 0; i < n_ratings; ++i)
    {
      for (unsigned int j = 0; j < n_labels; ++j)
        {
          double tmpdalpha[n_labels];
          auto double alphafunc (unsigned int);
          double alphafunc (unsigned int k)
            {
              if (k == j) { return 0.0; }
              else if (symmetric && k < j) 
                {
                  return alpha[ratings[i].worker * n_labels * n_labels +
                               k * n_labels +
                               j]; 
                }
              else 
                { 
                  return alpha[ratings[i].worker * n_labels * n_labels +
                               j * n_labels +
                               k]; 
                }
            }

          dlogbeta[ratings[i].image] += 
            pz[j + ratings[i].image * n_labels] * 
            dlogpratingdlogbeta (ratings[i].rating,
                                 alphafunc,
                                 logbeta[ratings[i].image],
                                 n_labels);

          dlogpratingdalpha (tmpdalpha,
                             ratings[i].rating,
                             alphafunc,
                             logbeta[ratings[i].image],
                             n_labels);

          for (unsigned int k = 0; k < n_labels; ++k)
            {
              if (k == j)
                {
                  /* do nothing ... */
                }
              else if (symmetric && k < j) 
                {
                  dalpha[ratings[i].worker * n_labels * n_labels +
                         k * n_labels +
                         j] += 
                    pz[j + ratings[i].image * n_labels] * tmpdalpha[k];
                }
              else
                {
                  dalpha[ratings[i].worker * n_labels * n_labels +
                         j * n_labels +
                         k] += 
                    pz[j + ratings[i].image * n_labels] * tmpdalpha[k];
                }
            }
        }
    }

  for (unsigned int i = 0; i < n_workers; ++i)
    {
      for (unsigned int j = 0; j < n_labels; ++j)
        {
          for (unsigned int k = 0; k < n_labels; ++k)
            {
              if (k == j)
                {
                  /* do nothing ... */
                }
              else if (symmetric && k < j) 
                {
                  dalpha[i * n_labels * n_labels +
                         k * n_labels +
                         j] += 
                    prioralpha->dlogpdf 
                      (alpha[i * n_labels * n_labels +
                             k * n_labels +
                             j],
                       prioralpha);
                }
              else
                {
                  dalpha[i * n_labels * n_labels +
                         j * n_labels +
                         k] += 
                    prioralpha->dlogpdf 
                      (alpha[i * n_labels * n_labels +
                             j * n_labels +
                             k],
                       prioralpha);
                }
            }
        }
    }

  for (unsigned int i = 0; i < n_images; ++i)
    {
      dlogbeta[i] += priorlogbeta->dlogpdf (logbeta[i], priorlogbeta);
    }
}
